Response to intestinal provocation monitored by transabdominal ultrasound in patients with food hypersensitivity

Owing to lack of objective measures, the diagnosis of food hypersensitivity may be difficult. The aim of this study was to investigate whether the intestinal response to direct provocation in patients with food hypersensitivity could be recognized by ultrasound.

Thirty-two patients with chronic abdominal complaints, self-attributed to food hypersensitivity/allergy were included in the study. Via a nasoduodenal tube, the duodenal mucosa was challenged with the suspected food item dissolved in 10 ml water or saline. Using external ultrasound, the sonographic features (wall thickness and diameter of the duodenal bulb and jejunum, peristalsis activity and luminal fluid) were recorded before and during one hour after challenge.

Sonographic changes were observed after challenge in 14 (44%) of the 32 patients. A positive sonographic response (increased wall thickness, diameter, peristalsis and/or luminal fluid) was significantly related to a positive skin prick test (p = 0.008) and a positive double-blind placebo-controlled food challenge (p = 0.03). A significant correlation was found between provocation-induced symptoms and wall thickness of the duodenal bulb (r = 0.50, p = 0.004) or the jejunum (r = 0.42, p = 0.02). Intra- and interobserver variation of the tracing procedure showed low values.

Responses of the proximal small intestines to direct provocation (swelling of the wall and exudation of fluid into the lumen) could be visualized by transabdominal ultrasound. This new provocation test could be helpful in the evaluation of patients with food hypersensitivity.